1. Field of the Invention
This invention relates to a blood perfusion system for percutaneous transluminal angioplasty to, for example, femoral and coronary arteries for the purpose of dilating the stenosis to improve blood flow therethrough. It also relates to tube means used in such a blood perfusion system.
2. Prior Art
In treating a stenosis in a vessel such as coronary artery, a dilation catheter having a balloon at a distal region thereof is inserted into the vessel until the balloon reaches the lesion. The balloon is then inflated to expand the stenosis. The inflated balloon inevitably blocks the relevant portion of the vessel to stop further blood flow. Continued blood flow interruption for some time is dangerous to the patient. Thus, if the operation takes a long time, it is critical to ensure normal blood flow by transporting a necessary amount of blood to the periphery of the lesion through the lumen of the dilation catheter.
The following two methods are known for such blood perfusion.
A first method is to previously collect blood in a blood bag from the patient herself or himself or another person. During the operation, the blood in storage is introduced into the lumen of the dilation catheter and injected to the periphery of the lesion.
A second method is to aspirate blood from another vessel of the patient under operation. The blood taken in is directly fed to the lumen of the dilation catheter and injected to the periphery of the lesion over the entire operation period.
However, the first method has a problem that the blood feed which has been in storage is less fresh and can cause infection. A problem of compatibility with the patient arises particularly when blood from another person is used.
The second method is advantageous in that fresh blood can be fed. Nevertheless, in addition to the site where the dilation catheter is inserted or the sheath is indwelled in the patient's vessel, a cutdown or puncture must be done at another site of the vessel (for example, a blood intake needle be punctured) for the purpose of aspirating blood. This adds to the burden to the patient. The additional burden is serious to old patients, the majority of patients who need a treatment to dilate a stenosis.